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Patented Mar. 6, 1923.

UNITED STATES WALTER GLAESER, OF BROOKLYN, NEW YORK.

MANUFACTURE OF SODIUM PHOSPHATE.

Io Drawing.

To all whom it may concern.-

Be it known that I WALTER Gmasaa, a citizen of the United tates, and a resident of Brooklyn, county of Kings, and State of New York, have invented a new and useful Improvement in the Manufacture of Sodium Phosphate, of which the following is a specification. the principle of the invention being herein explained and the best mode in which I have contemplated appl ing that principle, so as to distinguish it rom other inventions.

The present invention relates to the manufacture of sodium phosphates by means of the decomposition of insoluble phosphates in the form of phosphate rock by sodium chloride and sodium acid sulphate. (nitre cake), or equivalent substance. The principal object of the invention is the provision of such a process which shall be simple and relatively inexpensive, and can be carried out with wellknown and easily procured reagents.

My invention, then. consists of the steps hereinafter fully described and particularly pointed out in the claims. the following descriptions setting forth in detail certain steps embodying the invention. such disclosed steps constituting. however, but one of the various ways in which the principle of the invention may he used.

Phosphate rock may first he decomposed by means of a solution containing sodium chloride and sodium bi-sulphate (nitre cake). which has been slightly warmed to facilitate the reaction. the sodium chloride acting as a catalyzer. (by the formation of hydrochloric acid in a nascent condition and the re-formation of sodium chloride). The reaction which takes place at this point may be represented as follows After the removal of the calcium sulphate and other insoluble matter by filtration. or any other suitable method. the liquor is evaporated to dryness. during which operation some sodium phosphate is formed according to the equation below.

2H PO,+4NaCl:2Na HPO,+4HCl To secure further formation of a sodium phosphate the dried mass is heated to about 500 C. The reaction which takes place Application filed March 1, 1920. Serial No. 882,847.

during this heating step can be expressed by the equation:

If six molecules of sodium chloride are used instead of four, as in the above equation, trisodium phosphate is formed according to the following equation, however,

2H PO,+6NaCl=2Na PO,+6HCl The hydrochloric acid which is regained in each case may be utilized for the repetition of this cycle of reactions as indicated by the following equations If six molecules of hydrochloric acid are used the above reactions may be represented by the following equations 1 ca P.o,+oHci=3(aci en riir If sodium sulphate is used instead of nitre cake the above equations will be slightly varied. and the reactions may be represented.

I therefore particularly point out and distinctly claim as my invention 1. In a method of making a soluble phosphate, the steps which consist in dissolving 5 phosphate rock in a solution containing nitre cake and common salt under heat, thereby forming sodium phosphate.

2. In a method of making a soluble phosphate, the steps which consist in (lissolvin phosphate rock in a solution containing [11- 10 tre cake and comomn salt at about 500 C. thereby forming sodium phosphate.

Signed by me, this 17th day of January, 1920.

WALTER GLAESER. 

